Implement the overflow-anchor CSS property as an opt-out for ScrollAnchoring

third_party/WebKit/Source/core/style/ComputedStyleConstants.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 115 matching lines @@
 // Box decoration attributes. Not inherited.
 
 enum EBoxDecorationBreak { BoxDecorationBreakSlice, BoxDecorationBreakClone };
 
 // Box attributes. Not inherited.
 
 enum EBoxSizing { BoxSizingContentBox, BoxSizingBorderBox };
 
 // Random visual rendering model attributes. Not inherited.
 
+enum EOverflowAnchor {
+    AnchorVisible, AnchorNone, AnchorAuto
+};
+
 enum EOverflow {
     OverflowVisible, OverflowHidden, OverflowScroll, OverflowAuto, OverflowOverlay, OverflowPagedX, OverflowPagedY
 };
 
 enum EVerticalAlign {
     VerticalAlignBaseline,
     VerticalAlignMiddle,
     VerticalAlignSub,
     VerticalAlignSuper,
     VerticalAlignTextTop,
@@ skipping 463 matching lines @@
 
 enum AutoRepeatType {
     NoAutoRepeat,
     AutoFill,
     AutoFit
 };
 
 } // namespace blink
 
 #endif // ComputedStyleConstants_h